Atherosclerosis is a chronic inflammatory disease mediated by monocyte infiltration and cholesterol deposition into the subendothelial area, resulting in foam cell development. Probiotics are live bacteria that are beneficial for health when administered orally in adequate amounts. In this study, 8-week-old atherosclerosis-prone apolipoprotein E-deficient (ApoE(-/-)) mice were fed with or withoutLactobacillus plantarumATCC 14917 per day for 12 weeks. Serum was collected to analyse the lipid profile, oxidative status and proinflammatory cytokines. The heart was isolated to quantify the atherosclerotic lesion size in the aortic arch. Quantitative real-time polymerase chain reaction was performed to determine the expression levels of tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1 beta in the aorta. The proteins extracted from the aorta were used for Western blot analysis to assess the expression levels of nuclear factor kappa B (NF-kappa B) and inhibitor of NF-kappa B (I kappa B alpha). The composition of gut microbiota was also examined through high-throughput sequencing. Results showed that the daily consumption ofL. plantarumATCC 14917 had no effect on body weight and lipid profile.L. plantarumATCC 14917 treatment significantly inhibited atherosclerotic lesion formation. In addition, the oxLDL, MDA, TNF-alpha and IL-1 beta levels were significantly reduced, whereas the SOD level was induced in the bacteria + high-fat diet group. Furthermore, the administration ofL. plantarumATCC 14917 significantly attenuated I kappa B alpha protein degradation and inhibited the translocation of P65 subunits of NF-kappa B.L. plantarumATCC 14917 treatment also modulated the composition of gut microbiota in ApoE(-/-)mice. Our findings showed thatL. plantarumATCC 14917 supplementation decreases the progression of atherosclerotic lesion formation by alleviating the inflammatory process and lowering oxidative stress.